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Handheld projector

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The Nikon Coolpix S1000pj compact camera projecting an image using its built in projector.

A Handheld projector (also known as a pocket projector or mobile projector or pico projector) is an emerging technology that applies the use of a image projector in a handheld device. It is a response to the emergence of compact portable devices such as mobile phones, personal digital assistants, and digital cameras, which have sufficient storage capacity to handle presentation materials but little space to accommodate an attached display screen. Handheld projectors involve miniaturized hardware and software that can project digital images onto any nearby viewing surface, such as a wall. The system comprises five main parts:the battery the electronics, the laser light sources, the combiner optic, and the scanning mirrors. First, the electronics system turns the image into an electronic signal. Next the electronic signals drive laser light sources with different colors and intensities down different paths. In the combiner optic the different light paths are combined into one path demonstrating a palette of colors. Finally, the mirrors copy the image pixel by pixel and can then project the image. This entire system is compacted into one very tiny chip. An important design characteristic of a handheld projector is the ability to project a clear image, regardless of the physical characteristics of the viewing surface.

Overview

Major advances in imaging technology have allowed the introduction of hand-held (pico) type projectors. The concept was introduced by Explay in 2003 and shown to various consumer electronics players. Their solution was publicly announced through their relationship with Kopin in January 2005 [1] The first public showcase was by Digislide at the ANZA tech conference in October 2006. Insight Media market research [2] divided the leading players in this application into micro-display makers (e.g. TI's DLP, Himax, Micron / Displaytech and Syndiant LCoS, and Maradin, Microvision and bTendo MEMS scanners), light source makers (e.g. Lumileds, Osram, Cree LEDs and Corning, Nichia, Mitsubishi Lasers) and module makers (e.g. Jabil/Sypro DLP with LED, 3M LCoS with LED, Explay LCoS with Laser). Manufacturers have produced handheld projectors exhibiting high-resolution, good brightness, and low energy consumption in a slightly larger format than pico. However most LED projectors of the current pico size as of May 2009 have been widely criticized for having insufficient brightness for everyday use in a normally lit room.

Most micro projectors such as 3M’s MPro 110, Aiptek’s V10, AAXA's P2, and BeamBox's R-1 currently employ a single LCoS imager chip with single white LED which is recognized to offer lower cost, high resolution, and fast response at the expense of color quality. Newer models such as the 3M Mpro 120 employ color-sequential (RGB) LEDs in either single or triple architecture which offers improved color quality similar to DLP models but at a higher cost. Other projectors such as WowWee's Cinemin Swivel and Optoma’s PK201 employ TI’s DLP technology. While slightly lower in resolution than their LCoS counterparts due to the tiny mirrors used in DLP technology, 3-LED DLP projectors are generally regarded as having a higher contrast, better efficiency and lower power consumption as opposed color-sequential LCoS units and better color quality than white LED LCoS units. Laser scanning projectors such as Microvision's PicoP, bTendo, and AAXA's L1 offer very good color gamut and low power consumption due to the use of lasers as the light source and also present an image that is always in focus. However high speckle noise in the image remain a major challenge.

Applications

Handheld projector can be used for different applications than small conventional projectors. Since 2008[3] researchers are studying applications that are specifically designed for handheld projectors often using prototypes of mobile phones with an integrated projector.

Picture browsing

Recent mobile phones have the ability to store thousands of photos and can be used to take photos with resolutions up to several megapixels. Viewing the photos is restricted by the phones' small displays. Projector phones allow photographs to be shared with a larger audience.[4]. One study found that people preferred to view and share photos with projector phones compared to using conventional mobile phones[5]. The projected display allowed viewing of pictures by all present which is currently not possible using a single mobile device. Furthermore, people enjoyed looking at and talking together about the pictures.

Gaming

Handheld projectors, in particular projector phones, could offer new possibilities for mobile gaming as demonstrated by the adaptation of the PlayStation 3 game LittleBigPlanet. Players can sketch a world on a sheet of paper or use an existing physical configuration of objects and let the physics engine simulate physical procedures in this world to achieve game goals[6].

Hand gesture recognition

Size reduction of mobile devices is often limited by the size of the used display. Apart from the display a complete phone can be, for example, integrated in a headset. It has been demonstrated that pico projectors integrated in headsets could be used as interaction devices e.g. using additional hand and finger tracking[7][8].

Pointer-based Computer control

Combining a pico projector with a webcam, a laser pointer, and image processing software enables full control of any computing system via the laser pointer. Pointer on/off actions, motion patterns (e.g. dwell, repetitive visit, circles, etc.) and more can all be mapped to events which generate standard mouse or keyboard events, or user-programmable actions[9][10][11].

Footnotes

  1. ^ "Kopin Team up with Explay to Develop Nano-Projector Engine". 2005-01-04.
  2. ^ Brennesholtz 2008, p.84.
  3. ^ A. Hang, E. Rukzio, and A. Greaves "Projector Phone: A Study of Using Mobile Phones with Integrated Projector for Interaction with Maps" Proceedings of the Conference on Human-Computer Interaction with Mobile Devices and Services (MobileHCI), 2008.
  4. ^ A. Greaves and E. Rukzio, "View & Share: A Collaborative Media Viewing and Sharing Framework using a Projector Phone", Proceedings of the Workshop on Mobile Interaction with the Real World (MIRW), 2008.
  5. ^ A. Greaves and E. Rukzio, "View & Share: Exploring Co-Present Viewing and Sharing of Pictures using Personal Projection" Proceedings of the Workshop on Mobile Interaction with the Real World (MIRW), 2009.
  6. ^ M. Löchtefeld, J. Schöning, M. Rohs, and A. Krüger, "Mobile Little Big Planet: An Augmented Reality Game for Camera Projector Phones", Proceedings of the Workshop on Mobile Interaction with the Real World (MIRW), 2009.
  7. ^ P. Mistry, P. Maes, and L. Chang, "WUW - wear Ur world: a wearable gestural interface", Proceedings of the Conference on Human Factors in Computing Systems (CHI), 2009.
  8. ^ M. Baldauf and P. Fröhlich, "Supporting Hand Gesture Manipulation of Projected Content with Mobile Phones", Proceedings of the Workshop on Mobile Interaction with the Real World (MIRW), 2009.
  9. ^ US Patent #6,275,214, "[1]" Computer presentation system and method with optical tracking of wireless pointer
  10. ^ US Patent #6,952,198, "[2]" System and method for communication with enhanced optical pointer
  11. ^ US Patent #7,091,949, "[3] Computer presentation system and method with optical tracking of wireless pointer"

See also

References

  • Brennesholtz, M (2008). "Market Segment Analysis: Pico-Projectors", Insight Media
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